Human teeth are stained by adhesion of various staining substances, in addition to calculus and plaque, on the surfaces thereof, and are decreased in gloss. Such staining and a decrease in gloss are demanded to be prevented as much as possible also in terms of beauty. In order to solve such a problem, there have been developed various oral compositions in which phytic acid which is known to exert a removing effect on tobacco tar, a suppressing effect on calculus, and the like is used.
For example, Patent Literature 1 discloses an oral composition in which a specific amount of a phytic acid or a salt thereof and a specific amount of pyrophosphoric acid or a salt thereof are contained in combination in a specific mass ratio, and the composition rapidly removes a minute stain adhering to the surface of teeth to exert an excellent gloss-imparting effect. In addition, Patent Literature 2 discloses a composition for use in removal of a solid product, in which phytic acid or a salt thereof is contained in a specific amount and also the content of a polyvalent cation is restrained, and such a composition can have an excellent whitening effect on teeth and also impart gloss to teeth.
On the other hand, phytic acid tends to exhibit an increased feeling of astringency depending on the amount thereof, and may also result in deterioration in feeling upon use. In view of the circumstances, for example, Patent Literature 3 discloses a dentifrice composition in which phytic acid or a salt thereof and a specific organic resin powder are contained in combination in respective specific amounts, and the feeling of astringency derived from phytic acid is effectively planned to be decreased while an excellent whitening effect on teeth is retained. Moreover, Patent Literature 4 discloses a dentifrice composition which contains a phytic acid salt, a pyrophosphoric acid salt, a monofluorophosphoric acid salt and the like in respective specific amounts, to thereby enable to exert a cleaning effect on teeth and a whitening effect on teeth.
(Patent Literature 1) JP-A-2012-219058
(Patent Literature 2) JP-A-2010-150225
(Patent Literature 3) JP-A-2009-263281
(Patent Literature 4) CN-A-101690699